riched20: Return 0x0 size for NULL objects

[Nikolay Sivov]

Fixes a crash in https://bugs.winehq.org/show_bug.cgi?id=20830
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-riched20-Return-0x0-size-for-NULL-objects.patch
Type: text/x-patch
Size: 2683 bytes
Desc: not available
URL: <http://www.winehq.org/pipermail/wine-patches/attachments/20150603/276a6e0c/attachment.bin>